Vehicular trailer backup assist system

ABSTRACT

A vehicular trailer backup assist system is operable to steer a vehicle, with a trailer connected at the rear of the vehicle, during a reversing maneuver of the vehicle and trailer. The system electronically overlays a plurality of zones over displayed video images, with each individual zone of the overlayed plurality of zones being indicative of a respective individual region rearward of the vehicle and trailer. Responsive to a selected zone of travel for the trailer, the control controls steering of the vehicle to steer the vehicle to guide the trailer towards the respective individual region that is encompassed by the selected zone of travel during reversing of the vehicle and trailer. The driver of the vehicle manually adjusts steering of the vehicle to more accurately steer the vehicle towards a target location within the respective individual region that is encompassed by the selected zone of travel.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/613,441, filed Feb. 4, 2015, now U.S. Pat. No. 10,160,382,which claims the filing benefits of U.S. provisional applications, Ser.No. 61/972,708, filed Mar. 31, 2014, and Ser. No. 61/935,485, filed Feb.4, 2014, which are hereby incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates generally to a vehicle vision system for avehicle and, more particularly, to a vehicle vision system that utilizesone or more cameras at a vehicle.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties.

SUMMARY OF THE INVENTION

The present invention provides a camera for a vision system thatutilizes one or more cameras or image sensors to capture image data of ascene exterior (such as forwardly) of a vehicle and provides a displayof images indicative of or representative of the captured image data.

The vehicular vision system or trailer backup assist system of thepresent invention includes at least one camera disposed at a vehicle andhaving an exterior field of view rearward of the vehicle. The camera isoperable to capture image data. An image processor operable to processcaptured image data. Responsive to image processing of captured imagedata, the system is operable to determine a trailer angle of a trailerthat is towed by the vehicle. The system is responsive to the determinedtrailer angle and to a user input (that indicates a desired or selectedpath of the trailer) to adjust or control the steering of the vehicle toguide the trailer along the selected path. The system steers the vehicleto guide or backup the trailer in a direction that generally correspondsto the selected path or direction, and that is within a selected zone orrange of angles or directions rearward of the vehicle. The driver of thevehicle may manually adjust the steering of the vehicle to moreaccurately or precisely steer the vehicle in the desired direction, withthe system steering the vehicle generally in the desired direction sothat only minor or slight adjustments of vehicle steering may be neededor provided by the driver of the vehicle.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view of a vehicle with a vision system thatincorporates a camera and trailer backup assist system in accordancewith the present invention;

FIG. 1B is a plan view of a vehicle with another vision system thatincorporates a camera and trailer backup assist system in accordancewith the present invention;

FIG. 2 is a perspective view and illustration of different angles of thetrailer relative to the vehicle that the system may determine duringoperation of the vehicle and trailer backup assist system of the presentinvention;

FIG. 3 is a perspective view of a trailer being pulled by a vehicle witha target at the trailer;

FIG. 4 is a view of the target as viewed by the camera when the traileris turned relative to the vehicle;

FIGS. 5A-11A are perspective views of a trailer at different degrees ofturning relative to the towing vehicle;

FIGS. 5B-11B are top plan views showing the target at the trailer ofFIGS. 5A-11A, respectively;

FIG. 12 shows the plan views of FIGS. 6B, 11B, 8B, 9B, 7B and 10B sideby side; and

FIG. 13 is a schematic showing operation of a search algorithm of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or objectdetection system and/or alert system operates to capture images exteriorof the vehicle and may process the captured image data to display imagesand to detect objects at or near the vehicle and in the predicted pathof the vehicle, such as to assist a driver of the vehicle in maneuveringthe vehicle in a rearward direction. The vision system includes an imageprocessor or image processing system that is operable to receive imagedata from one or more cameras and provide an output to a display devicefor displaying images representative of the captured image data.Optionally, the vision system may provide a top down or bird's eye orsurround view display and may provide a displayed image that isrepresentative of the subject vehicle, and optionally with the displayedimage being customized to at least partially correspond to the actualsubject vehicle.

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 includes an imaging system or vision system 12that includes at least one exterior facing imaging sensor or camera,such as a rearward facing imaging sensor or camera 14 a (and the systemmay optionally include multiple exterior facing imaging sensors orcameras, such as a forwardly facing camera 14 b at the front (or at thewindshield) of the vehicle, and a sidewardly/rearwardly facing camera 14c, 14 d at respective sides of the vehicle), which captures imagesexterior of the vehicle, with the camera having a lens for focusingimages at or onto an imaging array or imaging plane or imager of thecamera (FIG. 1A). The vision system 12 includes a control or electroniccontrol unit (ECU) or processor 18 that is operable to process imagedata captured by the cameras and may provide displayed images at adisplay device 16 for viewing by the driver of the vehicle (althoughshown in FIG. 1A as being part of or incorporated in or at an interiorrearview mirror assembly 20 of the vehicle, the control 18 and/or thedisplay device may be disposed elsewhere at or in the vehicle). Forexample, and such as shown in FIG. 1B, the control may be close to orattached at or incorporated in a camera, such as the rear viewing camera14 a. The data transfer or signal communication from the camera to theECU may comprise any suitable data or communication link, such as avehicle network bus or the like of the equipped vehicle.

Driver assistant systems made to assist the driver when pulling orpushing a trailer without having a specific trailer angle sensor aredescribed in International Publication No. WO 2012/103193, publishedAug. 2, 2012, which is hereby incorporated herein by reference in itsentirety. Such trailer angle sensing systems may detect the trailernicking angle (relative to the vehicle) by determining the locationand/or angle of targets on the trailer via image processing of imagedata captured by the vision system's rearward viewing camera or cameras.In some systems, when attaching a trailer to the vehicle, the driver hasto enter its properties to put the trailer driving aid system into aposition to calculate the driving aids overlays properly, when backingup with the trailer attached. Such measurements and entries would needto be done for each different trailer that is connected to the vehicle.

The present invention provides a trailer backup assist system thatassists the driver of the vehicle 10 when reversing the vehicle with atrailer 22 connected thereto (FIGS. 1A, 1B and 2). The system isresponsive a user input 24 that, responsive to adjustment or selectionor setting of the input by the user or driver of the vehicle, sets orestablishes a rearward direction or path for the trailer to travel along(such as via a steering knob or dial that “steers” the trailer along itsrearward path). The system determines the angle of the trailer relativeto the vehicle (such as via image processing of image data captured bythe rear camera 14 a of the vehicle, which may include determination ofa location of a target 26 on the trailer) and, responsive to thedetermined angle and responsive to the user input (which may set orestablish a selected location or zone of the target 26 on the trailer toset a selected or desired direction of travel of the trailer), thesystem adjusts or controls the steering of the vehicle to generallyfollow the selected path of the trailer to assist the driver inreversing the vehicle and trailer.

For example, if zone 3 were selected (in FIG. 2), the system would steerthe vehicle and trailer (during a reversing maneuver) to guide thetrailer towards a region (such as towards the region or area occupied bythe vehicle shown in FIG. 2) that is encompassed by the selected zone,and may adjust the vehicle steering to guide and maintain the trailertravel direction towards the determined region or regions encompassed bythe selected zone. The driver then may only have to slightly adjust thesteering of the vehicle as the vehicle and trailer are reversing to moreaccurately steer the trailer to the desired location. The system mayutilize aspects of the systems described in U.S. patent application Ser.No. 14/102,981, filed Dec. 11, 2013, now U.S. Pat. No. 9,558,419; Ser.No. 14/036,723, filed Sep. 25, 2013, now U.S. Pat. No. 9,446,713, and/orSer. No. 13/979,871, filed Jul. 16, 2013, now U.S. Pat. No. 9,085,261,which are hereby incorporated herein by reference in their entireties.

The present invention thus may simplify customer interaction and humanmachine interface (HMI) during setup of the system, with a goal toeliminate user measurements during system and/or trailer setup. Thesystem is operable to modify the trailer backup assist (TBA) systemsteering algorithm in order to accommodate detection or measurementerror from the trailer angle detection (TAD) sensor or system. Thesystem may provide steering control of the vehicle that results in thetrailer being pushed or driven generally in the selected or desiredrearward direction, whereby the driver may use the steering wheel of thevehicle or the user input to further adjust or refine the steeringdirection to further control or guide the trailer in a more precisedesired or selected direction. The system of the present invention thusprovides a simplified steering algorithm for controlling the vehiclesteering, and does not require the detailed measurements during set upof the system on a vehicle with a trailer connected thereto.

The system of the present invention changes the assist system featureapproach from absolute trailer steering (such as an attempt to drive anytrailer on a defined trajectory or curve radius using knob utilizingmeasurements of the vehicle and trailer in an attempt to more accuratelyor precisely know where the trailer will be for any given vehiclesteering adjustment) to relative trailer steering (where the system maysteer the vehicle to generally position or guide the trailer towards adesired or selected direction of travel). This would move the controlmore to the driver of the vehicle, who may provide a finer adjustment ofthe steering of the vehicle as the vehicle and trailer are reversed.

The system reduces or eliminates user measurements for TAD, and mayprovide a display box as an overlay on the display screen (in thevehicle) and may instruct the user to move the trailer to place thetrailer target inside the box overlay. The TAD sensor then may outputthe zone in which the trailer is located. For example, and such as shownin FIG. 2, the trailer target (such as at or on the tongue of thetrailer) is located at one of the center regions or zones of theoverlay. The number of zones may vary depending on the particularapplication of the system. For example, the overlay may provide 20 zonesover roughly 180 degrees wide angle field of view, such that each zonesweeps or encompasses about nine degrees or thereabouts.

The zone indicates in which general direction (or angle or ranges ofangles relative to the vehicle) the trailer is moving. Because the usermeasurements are removed, an angle measurement is not needed, andnevertheless the TAD allows detection of the direction in which thetrailer is moving. The detected or determined or reported zone may notbe the same for two different trailer setups if the trailers have thesame trailer angle, but since the steering is relative, the impact isminimized.

The trailer backup assist system user input range or steering knob rangemay be divided into zones. The requested zone on the knob is mapped tothe reported zones of the TAD sensor. The steering algorithm attempts tosteer the trailer so that the selected angle of the knob matches thezone of the TAD. The TAD zone at zero degrees can still be identifiedusing the zero offset calibration, and the zones can be centered aroundzero degrees (or straight behind the vehicle).

Due to variations in vehicles and steering systems and trailers, thesame knob angle may result in a different curve radius for differenttrailers. This can be compared with different vehicles. Differentvehicles drive on a different curve radius when the steering wheel angleis the same depending on the vehicle wheel base and steering rackparameters and the like.

The trailer backup assist (TBA) system may not be able to steer thetrailer exactly at zero degrees. The driver may have to correct thesteering if the trailer drifts slightly off to one side. This may becompared to driving a vehicle on a road which slightly leans to oneside. The steering wheel has to be put on an angle to drive straight.Thus, the driver input or steering adjustment is small and is notdifferent from small adjustments that drivers typically have to doduring normal driving conditions.

Thus, the present invention will decrease setup complexity for trailerbackup assist systems, and will allow for less accuracy from the TADsensor but may receive more control input from the driver. The system ofthe present invention thus actively controls the vehicle and trailerduring a reversing maneuver. The rear camera and image processordetermine the target and the angle of trailer relative to the towvehicle and an output is generated indicative of that angle. The systemof the present invention adjusts the vehicle steering for the particulartrailer and vehicle configuration and for the selected direction oftravel of the vehicle and trailer. Because the system does not requirethe complicated measurements at the time of setup, the system issimplified and provides a simplified steering input to the vehicle. Thedriver selects the segment or zone that corresponds to the desireddirection of travel of the vehicle and trailer and the system generallysteers the trailer toward that direction. During the reversing maneuver,the driver can then override or adjust or slightly adjust or refine thevehicle steering (such as via the vehicle steering wheel or the userinput or dial) to steer the trailer more accurately in the selecteddirection or towards the target location (such as a selected boat launchramp or parking space or garage stall or loading/unloading station orthe like). The system operates to guide or steer the trailer close tothe desired direction of travel (within the selected zone or region orgeneral direction or range of angles) and the driver may then adjust thesteering accordingly as the trailer is moved rearwardly in that generaldirection. The steering algorithm of the control is thus simplified andthe system provides a trailer backup assist that can be implemented on awide range of vehicles and trailers without complex setup measurementsand processes.

Both when using a TBA system as described above with decreased setupcomplexity, or when using a system without and when using target basedto TDA algorithm, the finding of the trailer target by image processing(of image data captured by a rear camera of the vehicle) in the rearimage is important. This is not always a trivial problem. Typically,these targets should be as small as about 2 square inches. Due to thewide angle lens and because the rear camera is typically equipped withlow resolution imagers such as 1.2 MP and about 180 degree fisheye lenscameras, the checkerboard target 26 such as shown in FIGS. 3-13 iscaptured by just about 10×20 pixels. Typically, the rear vehicle sceneis mostly illuminated by scattered light, shattered light, stray lightor brindle (such as to be seen in exemplary FIGS. 11A and 11B) or thebackground itself is brindle such as at times when the ground is coveredwith leaves. For having a vehicle trailer angle detection target 26 withminimal auto correlation and rotation invariance, a Baker target may beused, such as described in U.S. patent application Ser. No. 14/102,981,filed Dec. 11, 2013, now U.S. Pat. No. 9,558,409, which is herebyincorporated herein by reference in its entirety. Due to the limitedtarget size, the resolution may be less for using a Baker target.Because of that, less sophisticated targets with conventional patternssuch as black and white chessboard pattern may find use, such as shownin the exemplary cases in the FIGS. 3-13 and especially in FIG. 4. Whenusing cameras with higher resolution or bigger targets, the use of Bakertargets instead of chessboard targets may be preferred.

Algorithms for finding target patterns within camera views such as rearcamera fisheye views or demorphed rear camera views typically check thewhole image or check the image portion which is below the horizon or maycheck a limited region of interest, for finding the target pattern.Since the trailer 22 turns around a turning point at the hitch 28 head,the target turns with the trailer. Because the viewing angle from thecamera to the target is comparably flat, the checkerboard squares appearas rhombs in a two dimensional (2D) camera image due to the perspectivewhen the target is turned against the camera view (see FIG. 4). As canbe seen in FIG. 2, a trailer target fixedly attached to a trailer turnsradially around the turning point of the hitch head with the vehicle.When the trailer-vehicle train stands on a balled surface, the targetturns a little downwardly, when the trailer-vehicle train stands in asink, the target turns a little upwardly within the camera view, but theturning radius stays substantially curved (arch-shaped area).

As an aspect of the present invention, the system may execute a fewtransformations of just the area the trailer target can possibly belocated (the arch-shaped area) plus a small tolerance area. The fewtransformations may be of a nature that the substantially curved area(arch-shaped area) may be bent (transformed) to a string shape area suchas ‘parallel projection’-transformation. That kind of viewtransformation is different to known art view point transformation, suchas top view (or top down or bird's eye or surround view) transformation.Straight lines become curved and curved lines may straighten, comparethe two straight (real scene) lane markings 40 a and 40 b in thedemorphed fisheye view of FIG. 5A to the target turning curve(arch-shaped) area parallel projection transformed view of FIG. 5B.FIGS. 6A-11A show more scenes with the trailer hooked onto the hitch indifferent turning angles. FIGS. 6B-11B show the relating viewstransformed views of the target area according the invention. In FIG.12, the FIGS. 6B-11B are arranged side by side depending on the turningangle. Starting from the left (FIG. 6B), with the trailer is turned tothe right, to the very right (FIG. 10B) with the trailer turned to theleft (related to the vehicle's middle axis (x-dimension)).

As can be seen with reference to FIG. 12, the benefit of the suggestedview transformation and pattern search area becomes clear. The patternis always orientated in the same way, but shifted sideward within theview area. By using such transformed views, a pattern search and comparealgorithm can easily find the target's position within the view, whichcan directly be set into relation to the trailer's turning angle.

A typical pattern search method is convolution. A 1×10 convolution mayfind use here. The search may run over the search area from left toright in lines such as shown in the example in FIG. 13 (at I). In therethe convolution search may run through line a then through line b andthen through line c. FIG. 13 (at II) shows a possible transformed inputimage with a target visible in the left third. A pattern which theconvolution search may detect the reference target matching at positionwas marked with a lightning shape in line b of FIG. 13 (at III).Optionally, more sophisticated search strategies may take previouslyfound positions into account the search may begin and hover around nearthe position an earlier search found the reference target matching atfor fastest and low performance consuming search.

The camera is disposed at a rear portion of the vehicle and has a fieldof view generally rearward of the vehicle. The camera may capture imagedata for use by the trailer backup assist system of the presentinvention, and may also capture image data for use by other vehiclesystems, such as a rear backup assist system or a surround view systemor the like.

The camera or sensor may comprise any suitable camera or sensor.Optionally, the camera may comprise a “smart camera” that includes theimaging sensor array and associated circuitry and image processingcircuitry and electrical connectors and the like as part of a cameramodule, such as by utilizing aspects of the vision systems described inInternational Publication Nos. WO 2013/081984 and/or WO 2013/081985,which are hereby incorporated herein by reference in their entireties.

The system includes an image processor operable to process image datacaptured by the camera or cameras, such as for detecting objects orother vehicles or pedestrians or the like in the field of view of one ormore of the cameras. For example, the image processor may comprise anEYEQ2 or EYEQ3 image processing chip available from Mobileye VisionTechnologies Ltd. of Jerusalem, Israel, and may include object detectionsoftware (such as the types described in U.S. Pat. Nos. 7,855,755;7,720,580 and/or 7,038,577, which are hereby incorporated herein byreference in their entireties), and may analyze image data to detectvehicles and/or other objects. Responsive to such image processing, andwhen an object or other vehicle is detected, the system may generate analert to the driver of the vehicle and/or may generate an overlay at thedisplayed image to highlight or enhance display of the detected objector vehicle, in order to enhance the driver's awareness of the detectedobject or vehicle or hazardous condition during a driving maneuver ofthe equipped vehicle.

The vehicle may include any type of sensor or sensors, such as imagingsensors or radar sensors or lidar sensors or ladar sensors or ultrasonicsensors or the like. The imaging sensor or camera may capture image datafor image processing and may comprise any suitable camera or sensingdevice, such as, for example, a two dimensional array of a plurality ofphotosensor elements arranged in at least 640 columns and 480 rows (atleast a 640×480 imaging array, such as a megapixel imaging array or thelike), with a respective lens focusing images onto respective portionsof the array. The photosensor array may comprise a plurality ofphotosensor elements arranged in a photosensor array having rows andcolumns. Preferably, the imaging array has at least 300,000 photosensorelements or pixels, more preferably at least 500,000 photosensorelements or pixels and more preferably at least 1 million photosensorelements or pixels. The imaging array may capture color image data, suchas via spectral filtering at the array, such as via an RGB (red, greenand blue) filter or via a red/red complement filter or such as via anRCC (red, clear, clear) filter or the like. The logic and controlcircuit of the imaging sensor may function in any known manner, and theimage processing and algorithmic processing may comprise any suitablemeans for processing the images and/or image data.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 7,005,974;5,760,962; 5,877,897; 5,796,094; 5,949,331; 6,222,447; 6,302,545;6,396,397; 6,498,620; 6,523,964; 6,611,202; 6,201,642; 6,690,268;6,717,610; 6,757,109; 6,802,617; 6,806,452; 6,822,563; 6,891,563;6,946,978; 7,859,565; 5,550,677; 5,670,935; 6,636,258; 7,145,519;7,161,616; 7,230,640; 7,248,283; 7,295,229; 7,301,466; 7,592,928;7,881,496; 7,720,580; 7,038,577; 6,882,287; 5,929,786 and/or 5,786,772,and/or International Publication Nos. 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No. 13/847,815, filed Mar. 20, 2013, andpublished Oct. 31, 2013 as U.S. Patent Publication No. 2013/0286193;Ser. No. 13/800,697, filed Mar. 13, 2013, and published Oct. 3, 2013 asU.S. Patent Publication No. 2013/0258077; Ser. No. 13/785,099, filedMar. 5, 2013, now U.S. Pat. No. 9,565,342; Ser. No. 13/779,881, filedFeb. 28, 2013, now U.S. Pat. No. 8,694,224; Ser. No. 13/774,317, filedFeb. 22, 2013, now U.S. Pat. No. 9,269,263; Ser. No. 13/774,315, filedFeb. 22, 2013, and published Aug. 22, 2013 as U.S. Patent PublicationNo. 2013/0215271; Ser. No. 13/681,963, filed Nov. 20, 2012, now U.S.Pat. No. 9,264,673; Ser. No. 13/660,306, filed Oct. 25, 2012, now U.S.Pat. No. 9,146,898; Ser. No. 13/653,577, filed Oct. 17, 2012, now U.S.Pat. No. 9,174,574; and/or Ser. No. 13/534,657, filed Jun. 27, 2012, andpublished on Jan. 3, 2013 as U.S. Patent Publication No.US-2013/0002873, which are all hereby incorporated herein by referencein their entireties. The system may communicate with other communicationsystems via any suitable means, such as by utilizing aspects of thesystems described in International Publication Nos. WO/2010/144900; WO2013/043661 and/or WO 2013/081985, and/or U.S. patent application Ser.No. 13/202,005, filed Aug. 17, 2011, now U.S. Pat. No. 9,126,525, whichare hereby incorporated herein by reference in their entireties.

The imaging device and control and image processor and any associatedillumination source, if applicable, may comprise any suitablecomponents, and may utilize aspects of the cameras and vision systemsdescribed in U.S. Pat. Nos. 5,550,677; 5,877,897; 6,498,620; 5,670,935;5,796,094; 6,396,397; 6,806,452; 6,690,268; 7,005,974; 7,937,667;7,123,168; 7,004,606; 6,946,978; 7,038,577; 6,353,392; 6,320,176;6,313,454 and 6,824,281, and/or International Publication Nos. WO2010/099416; WO 2011/028686 and/or WO 2013/016409, and/or U.S. Pat.Publication No. US 2010-0020170, and/or U.S. patent application Ser. No.13/534,657, filed Jun. 27, 2012, and published on Jan. 3, 2013 as U.S.Patent Publication No. US-2013/0002873, which are all herebyincorporated herein by reference in their entireties. The camera orcameras may comprise any suitable cameras or imaging sensors or cameramodules, and may utilize aspects of the cameras or sensors described inU.S. patent application Ser. No. 13/260,400, filed Sep. 26, 2011, nowU.S. Pat. No. 8,542,451, and/or U.S. Publication No. US-2009-0244361,and/or U.S. Pat. Nos. 7,965,336 and/or 7,480,149, which are herebyincorporated herein by reference in their entireties. The imaging arraysensor may comprise any suitable sensor, and may utilize various imagingsensors or imaging array sensors or cameras or the like, such as a CMOSimaging array sensor, a CCD sensor or other sensors or the like, such asthe types described in U.S. Pat. Nos. 5,550,677; 5,670,935; 5,760,962;5,715,093; 5,877,897; 6,922,292; 6,757,109; 6,717,610; 6,590,719;6,201,642; 6,498,620; 5,796,094; 6,097,023; 6,320,176; 6,559,435;6,831,261; 6,806,452; 6,396,397; 6,822,563; 6,946,978; 7,339,149;7,038,577; 7,004,606; 7,720,580 and/or 7,965,336, and/or InternationalPublication Nos. WO/2009/036176 and/or WO/2009/046268, which are allhereby incorporated herein by reference in their entireties.

The camera module and circuit chip or board and imaging sensor may beimplemented and operated in connection with various vehicularvision-based systems, and/or may be operable utilizing the principles ofsuch other vehicular systems, such as a vehicle headlamp control system,such as the type disclosed in U.S. Pat. Nos. 5,796,094; 6,097,023;6,320,176; 6,559,435; 6,831,261; 7,004,606; 7,339,149 and/or 7,526,103,which are all hereby incorporated herein by reference in theirentireties, a rain sensor, such as the types disclosed in commonlyassigned U.S. Pat. Nos. 6,353,392; 6,313,454; 6,320,176 and/or7,480,149, which are hereby incorporated herein by reference in theirentireties, a vehicle vision system, such as a forwardly, sidewardly orrearwardly directed vehicle vision system utilizing principles disclosedin U.S. Pat. Nos. 5,550,677; 5,670,935; 5,760,962; 5,877,897; 5,949,331;6,222,447; 6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202;6,201,642; 6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452;6,822,563; 6,891,563; 6,946,978 and/or 7,859,565, which are all herebyincorporated herein by reference in their entireties, a trailer hitchingaid or tow check system, such as the type disclosed in U.S. Pat. No.7,005,974, which is hereby incorporated herein by reference in itsentirety, a reverse or sideward imaging system, such as for a lanechange assistance system or lane departure warning system or for a blindspot or object detection system, such as imaging or detection systems ofthe types disclosed in U.S. Pat. Nos. 7,881,496; 7,720,580; 7,038,577;5,929,786 and/or 5,786,772, and/or U.S. provisional applications, Ser.No. 60/628,709, filed Nov. 17, 2004; Ser. No. 60/614,644, filed Sep. 30,2004; Ser. No. 60/618,686, filed Oct. 14, 2004; Ser. No. 60/638,687,filed Dec. 23, 2004, which are hereby incorporated herein by referencein their entireties, a video device for internal cabin surveillanceand/or video telephone function, such as disclosed in U.S. Pat. Nos.5,760,962; 5,877,897; 6,690,268 and/or 7,370,983, and/or U.S.Publication No. US-2006-0050018, which are hereby incorporated herein byreference in their entireties, a traffic sign recognition system, asystem for determining a distance to a leading or trailing vehicle orobject, such as a system utilizing the principles disclosed in U.S. Pat.Nos. 6,396,397 and/or 7,123,168, which are hereby incorporated herein byreference in their entireties, and/or the like.

Optionally, the circuit board or chip may include circuitry for theimaging array sensor and or other electronic accessories or features,such as by utilizing compass-on-a-chip or EC driver-on-a-chip technologyand aspects such as described in U.S. Pat. Nos. 7,255,451 and/or7,480,149, and/or U.S. Publication No. US-2006-0061008, and/or U.S.patent application Ser. No. 12/578,732, filed Oct. 14, 2009, now U.S.Pat. No. 9,487,144, which are hereby incorporated herein by reference intheir entireties.

Optionally, the vision system may include a display for displayingimages captured by one or more of the imaging sensors for viewing by thedriver of the vehicle while the driver is normally operating thevehicle. Optionally, for example, the vision system may include a videodisplay device disposed at or in the interior rearview mirror assemblyof the vehicle, such as by utilizing aspects of the video mirror displaysystems described in U.S. Pat. No. 6,690,268 and/or U.S. patentapplication Ser. No. 13/333,337, filed Dec. 21, 2011, now U.S. Pat. No.9,264,672, which are hereby incorporated herein by reference in theirentireties. The video mirror display may comprise any suitable devicesand systems and optionally may utilize aspects of the compass displaysystems described in U.S. Pat. Nos. 7,370,983; 7,329,013; 7,308,341;7,289,037; 7,249,860; 7,004,593; 4,546,551; 5,699,044; 4,953,305;5,576,687; 5,632,092; 5,677,851; 5,708,410; 5,737,226; 5,802,727;5,878,370; 6,087,953; 6,173,508; 6,222,460; 6,513,252 and/or 6,642,851,and/or European patent application, published Oct. 11, 2000 underPublication No. EP 0 1043566, and/or U.S. Publication No.US-2006-0061008, which are all hereby incorporated herein by referencein their entireties. Optionally, the video mirror display screen ordevice may be operable to display images captured by a rearward viewingcamera of the vehicle during a reversing maneuver of the vehicle (suchas responsive to the vehicle gear actuator being placed in a reversegear position or the like) to assist the driver in backing up thevehicle, and optionally may be operable to display the compass headingor directional heading character or icon when the vehicle is notundertaking a reversing maneuver, such as when the vehicle is beingdriven in a forward direction along a road (such as by utilizing aspectsof the display system described in International Publication No. WO2012/051500, which is hereby incorporated herein by reference in itsentirety).

Optionally, the vision system (utilizing the forward facing camera and arearward facing camera and other cameras disposed at the vehicle withexterior fields of view) may be part of or may provide a display of atop-down view or birds-eye view system of the vehicle or a surround viewat the vehicle, such as by utilizing aspects of the vision systemsdescribed in International Publication Nos. WO 2010/099416; WO2011/028686; WO 2012/075250; WO 2013/019795; WO 2012/075250; WO2012/145822; WO 2013/081985; WO 2013/086249 and/or WO 2013/109869,and/or U.S. patent application Ser. No. 13/333,337, filed Dec. 21, 2011,now U.S. Pat. No. 9,264,672, which are hereby incorporated herein byreference in their entireties.

Optionally, a video mirror display may be disposed rearward of andbehind the reflective element assembly and may comprise a display suchas the types disclosed in U.S. Pat. Nos. 5,530,240; 6,329,925;7,855,755; 7,626,749; 7,581,859; 7,446,650; 7,370,983; 7,338,177;7,274,501; 7,255,451; 7,195,381; 7,184,190; 5,668,663; 5,724,187 and/or6,690,268, and/or in U.S. Publication Nos. US-2006-0061008 and/orUS-2006-0050018, which are all hereby incorporated herein by referencein their entireties. The display is viewable through the reflectiveelement when the display is activated to display information. Thedisplay element may be any type of display element, such as a vacuumfluorescent (VF) display element, a light emitting diode (LED) displayelement, such as an organic light emitting diode (OLED) or an inorganiclight emitting diode, an electroluminescent (EL) display element, aliquid crystal display (LCD) element, a video screen display element orbacklit thin film transistor (TFT) display element or the like, and maybe operable to display various information (as discrete characters,icons or the like, or in a multi-pixel manner) to the driver of thevehicle, such as passenger side inflatable restraint (PSIR) information,tire pressure status, and/or the like. The mirror assembly and/ordisplay may utilize aspects described in U.S. Pat. Nos. 7,184,190;7,255,451; 7,446,924 and/or 7,338,177, which are all hereby incorporatedherein by reference in their entireties. The thicknesses and materialsof the coatings on the substrates of the reflective element may beselected to provide a desired color or tint to the mirror reflectiveelement, such as a blue colored reflector, such as is known in the artand such as described in U.S. Pat. Nos. 5,910,854; 6,420,036 and/or7,274,501, which are hereby incorporated herein by reference in theirentireties.

Optionally, the display or displays and any associated user inputs maybe associated with various accessories or systems, such as, for example,a tire pressure monitoring system or a passenger air bag status or agarage door opening system or a telematics system or any other accessoryor system of the mirror assembly or of the vehicle or of an accessorymodule or console of the vehicle, such as an accessory module or consoleof the types described in U.S. Pat. Nos. 7,289,037; 6,877,888;6,824,281; 6,690,268; 6,672,744; 6,386,742 and/or 6,124,886, and/or U.S.Publication No. US-2006-0050018, which are hereby incorporated herein byreference in their entireties.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent lawincluding the doctrine of equivalents.

The invention claimed is:
 1. A vehicular trailer backup assist system, said vehicular trailer backup assist system comprising: a camera disposed at a vehicle and having a field of view exterior and at least rearward of the vehicle; wherein, with a trailer hitched at a trailer hitch of the vehicle, the field of view of said camera at least partially encompasses the trailer; a control comprising an image processor that processes image data captured by said camera; wherein image data captured by said camera is processed at said control; a display screen disposed in the vehicle and viewable by a driver of the vehicle when operating the vehicle, wherein, during a reversing maneuver of the vehicle and trailer, said display screen displays video images derived at least in part from image data captured by said camera; wherein, during the reversing maneuver of the vehicle and trailer, said vehicular trailer backup assist system electronically overlays a plurality of zones over the video images displayed at said display screen, and wherein each individual zone of the overlayed plurality of zones is indicative of a respective individual region rearward of the vehicle and trailer; a user input operable by a driver of the vehicle, wherein the driver operates the user input to select an individual zone of the overlayed plurality of zones as a zone of travel for the trailer during the reversing maneuver of the vehicle; wherein, responsive to the selected zone of travel for the trailer, said control controls, during the reversing maneuver of the vehicle and trailer, steering of the vehicle to steer the vehicle such that, during the reversing maneuver, the trailer travels towards the respective individual region displayed in the displayed video images that is encompassed by the overlay of the selected zone of travel; wherein said control controls steering of the vehicle to move the trailer relative to the overlayed plurality of zones in a manner that guides the trailer towards the respective individual region that is encompassed by the overlay of the selected zone of travel during reversing of the vehicle and trailer; and wherein, during the reversing maneuver of the vehicle and trailer, the driver of the vehicle manually adjusts steering of the vehicle to more accurately steer the vehicle towards a target location within the respective individual region that is encompassed by the overlay of the selected zone of travel.
 2. The vehicular trailer backup assist system of claim 1, wherein said control, responsive at least in part to processing at said control of image data captured by said camera, determines a trailer angle of the trailer relative to a longitudinal axis of the vehicle.
 3. The vehicular trailer backup assist system of claim 2, wherein said control, via processing at said control of image data captured by said camera, determines the trailer angle of the trailer via determining a location of a target disposed at the trailer.
 4. The vehicular trailer backup assist system of claim 3, wherein image data captured by said camera is demorphed by processing at said control before said control determines the location of the target disposed at the trailer.
 5. The vehicular trailer backup assist system of claim 4, wherein said image data, when demorphed by processing at said control, results in straightened lines in regions of image data captured by said camera.
 6. The vehicular trailer backup assist system of claim 1, wherein said control, via processing at said control of image data captured by said camera, determines an orientation of the trailer relative to a longitudinal axis of the vehicle via determining a location of a target disposed at the trailer.
 7. The vehicular trailer backup assist system of claim 6, wherein, with the trailer hitched at the trailer hitch of the vehicle, said control determines a zone of the overlayed plurality of zones where the target disposed at the trailer is located, and wherein steering of the vehicle is controlled responsive at least in part to the determined zone.
 8. The vehicular trailer backup assist system of claim 7, wherein the overlayed plurality of zones comprises an overlay of a plurality of pie-shaped zones electronically overlayed over the video images displayed at said display screen so as to appear over the displayed video images and partially surrounding the trailer hitch of the vehicle.
 9. The vehicular trailer backup assist system of claim 8, wherein said control controls steering of the vehicle to maintain the target disposed at the trailer in the selected zone of travel.
 10. The vehicular trailer backup assist system of claim 1, wherein the overlayed plurality of zones comprises an overlay of a plurality of pie-shaped zones electronically overlayed over the video images displayed at said display screen so as to appear over the displayed video images and partially surrounding the trailer hitch of the vehicle.
 11. The vehicular trailer backup assist system of claim 10, wherein said control controls steering of the vehicle to maintain a portion of the trailer in the selected zone of travel during reversing of the vehicle and trailer.
 12. A vehicular trailer backup assist system, said vehicular trailer backup assist system comprising: a camera disposed at a vehicle and having a field of view exterior and at least rearward of the vehicle; wherein, with a trailer hitched at a trailer hitch of the vehicle, the field of view of said camera at least partially encompasses the trailer; a control comprising an image processor that processes image data captured by said camera; wherein image data captured by said camera is processed at said control; a display screen disposed in the vehicle and viewable by a driver of the vehicle when operating the vehicle, wherein, during a reversing maneuver of the vehicle and trailer, said display screen displays video images derived at least in part from image data captured by said camera; wherein, during the reversing maneuver of the vehicle and trailer, said vehicular trailer backup assist system electronically overlays a plurality of zones over the video images displayed at said display screen, and wherein each individual zone of the overlayed plurality of zones is indicative of a respective individual region rearward of the vehicle and trailer; wherein the overlayed plurality of zones comprises an overlay of a plurality of pie-shaped zones electronically overlayed over the video images displayed at said display screen so as to appear over the displayed video images and partially surrounding the trailer hitch of the vehicle; wherein said control, via processing at said control of image data captured by said camera, determines an orientation of the trailer relative to a longitudinal axis of the vehicle via determining a location of a target disposed at the trailer; a user input operable by a driver of the vehicle, wherein the driver operates the user input to select an individual zone of the overlayed plurality of zones as a zone of travel for the trailer during the reversing maneuver of the vehicle; wherein, responsive to the selected zone of travel for the trailer, said control controls, during the reversing maneuver of the vehicle and trailer, steering of the vehicle to steer the vehicle such that, during the reversing maneuver, the trailer travels towards the respective individual region displayed in the displayed video images that is encompassed by the overlay of the selected zone of travel; wherein said control controls steering of the vehicle to move the trailer relative to the overlayed plurality of zones in a manner that guides the trailer towards the respective individual region that is encompassed by the overlay of the selected zone of travel during reversing of the vehicle and trailer; and wherein, during the reversing maneuver of the vehicle and trailer, the driver of the vehicle manually adjusts steering of the vehicle to more accurately steer the vehicle towards a target location within the respective individual region that is encompassed by the overlay of the selected zone of travel.
 13. The vehicular trailer backup assist system of claim 12, wherein image data captured by said camera is demorphed by processing at said control before said control determines the location of the target disposed at the trailer.
 14. The vehicular trailer backup assist system of claim 13, wherein said image data, when demorphed by processing at said control, results in straightened lines in regions of image data captured by said camera.
 15. The vehicular trailer backup assist system of claim 12, wherein, with the trailer hitched at the trailer hitch of the vehicle, said control determines a zone of the overlayed plurality of zones where the target disposed at the trailer is located, and wherein steering of the vehicle is controlled responsive at least in part to the determined zone.
 16. The vehicular trailer backup assist system of claim 15, wherein said control controls steering of the vehicle to maintain the target disposed at the trailer in the selected zone of travel.
 17. A vehicular trailer backup assist system, said vehicular trailer backup assist system comprising: a camera disposed at a vehicle and having a field of view exterior and at least rearward of the vehicle; wherein, with a trailer hitched at a trailer hitch of the vehicle, the field of view of said camera at least partially encompasses the trailer; a control comprising an image processor that processes image data captured by said camera; wherein image data captured by said camera is processed at said control; a display screen disposed in the vehicle and viewable by a driver of the vehicle when operating the vehicle, wherein, during a reversing maneuver of the vehicle and trailer, said display screen displays video images derived at least in part from image data captured by said camera; wherein, during the reversing maneuver of the vehicle and trailer, said vehicular trailer backup assist system electronically overlays a plurality of zones over the video images displayed at said display screen, and wherein each individual zone of the overlayed plurality of zones is indicative of a respective individual region rearward of the vehicle and trailer; wherein said control, via processing at said control of image data captured by said camera, determines an orientation of the trailer relative to a longitudinal axis of the vehicle via determining a location of a target disposed at the trailer; wherein image data captured by said camera is demorphed by processing at said control before said control determines the location of the target disposed at the trailer; a user input operable by a driver of the vehicle, wherein the driver operates the user input to select an individual zone of the overlayed plurality of zones as a zone of travel for the trailer during the reversing maneuver of the vehicle; wherein, responsive to the selected zone of travel for the trailer, said control controls, during the reversing maneuver of the vehicle and trailer, steering of the vehicle to steer the vehicle such that, during the reversing maneuver, the trailer travels towards the respective individual region displayed in the displayed video images that is encompassed by the overlay of the selected zone of travel; wherein said control controls steering of the vehicle to move the trailer relative to the overlayed plurality of zones in a manner that guides the trailer towards the respective individual region that is encompassed by the overlay of the selected zone of travel during reversing of the vehicle and trailer; wherein, with the trailer hitched at the trailer hitch of the vehicle, said control determines a zone of the overlayed plurality of zones where the target disposed at the trailer is located, and wherein steering of the vehicle is controlled responsive at least in part to the determined zone where the target disposed at the trailer is located; and wherein, during the reversing maneuver of the vehicle and trailer, the driver of the vehicle manually adjusts steering of the vehicle to more accurately steer the vehicle towards a target location within the respective individual region that is encompassed by the overlay of the selected zone of travel.
 18. The vehicular trailer backup assist system of claim 17, wherein said image data, when demorphed by processing at said control, results in straightened lines in regions of image data captured by said camera.
 19. The vehicular trailer backup assist system of claim 18, wherein the overlayed plurality of zones comprises an overlay of a plurality of pie-shaped zones electronically overlayed over the video images displayed at said display screen so as to appear over the displayed video images and partially surrounding the trailer hitch of the vehicle.
 20. The vehicular trailer backup assist system of claim 19, wherein said control controls steering of the vehicle to maintain the target disposed at the trailer in the selected zone of travel. 